How to make an iPhone transmit an iBeacon

Swift version: 5.1

Paul Hudson @twostraws May 28th 2019

iOS 7.0 introduced not only the ability to detect iBeacons, but also the ability to create iBeacons – for iPhones and iPads to broadcast their own beacon signal that can then be detected by other devices. To make this work, you add these two imports:

import CoreBluetooth
import CoreLocation

Now you need to make your view controller (or other class) conform to the CBPeripheralManagerDelegate protocol so that it’s capable of handling Bluetooth state changes. You also need to create three properties: the beacon itself, plus two Bluetooth properties that store configuration and management information.

Once that’s done, there are three methods you need to include. The first one creates the beacon and starts broadcasting, the second one stops the beacon, and the third one acts as an intermediary between your app and the iOS Bluetooth stack.

Here’s a working example to get you started:

class ViewController: UIViewController, CBPeripheralManagerDelegate {
    var localBeacon: CLBeaconRegion!
    var beaconPeripheralData: NSDictionary!
    var peripheralManager: CBPeripheralManager!

    func initLocalBeacon() {
        if localBeacon != nil {
            stopLocalBeacon()
        }

        let localBeaconUUID = "5A4BCFCE-174E-4BAC-A814-092E77F6B7E5"
        let localBeaconMajor: CLBeaconMajorValue = 123
        let localBeaconMinor: CLBeaconMinorValue = 456

        let uuid = UUID(uuidString: localBeaconUUID)!
        localBeacon = CLBeaconRegion(proximityUUID: uuid, major: localBeaconMajor, minor: localBeaconMinor, identifier: "Your private identifer here")

        beaconPeripheralData = localBeacon.peripheralData(withMeasuredPower: nil)
        peripheralManager = CBPeripheralManager(delegate: self, queue: nil, options: nil)
    }

    func stopLocalBeacon() {
        peripheralManager.stopAdvertising()
        peripheralManager = nil
        beaconPeripheralData = nil
        localBeacon = nil
    }

    func peripheralManagerDidUpdateState(_ peripheral: CBPeripheralManager) {
        if peripheral.state == .poweredOn {
            peripheralManager.startAdvertising(beaconPeripheralData as? [String: Any])
        } else if peripheral.state == .poweredOff {
            peripheralManager.stopAdvertising()
        }
    }
}